File 'gui/watchman.cls' (part of 'Pool_GuiBase')

Description (short): value management (-value), as in Tix
Written by: Andreas Kupries
Description: management for option -variable of a widget displaying a single value. Actually a stripped down version of valueManager.
Keywords: value management, -value, widgets

Class 'watchManager'

Description

Defines and manages the option '-variable'. Derived classes must provide a method 'updateDisplay'. It will be called after changes to the value and has to refresh the shown information according to the changed value.

Superclasses

widget

Options

variable

Methods

public: InitializeManager ()
TrackVarContents (var idx op)
TrackVariable (o oldValue)
updateDisplay ()
watchManager ()
~watchManager ()

Membervariables

public: value

Options

-variable: Name of the (global) variable associated to the widget. Any changes to its contents are propagated into the widget and vice versa.

Methods

InitializeManager ()

Special method, is called after the completion of the construction of widget and its components. Initializes the value of the widget according to the contents of the associated variable, if defined.

TrackVarContents (var idx op)

Internal trace callback to monitor the value of the variable associated to the widget.

Argument: var Standard trace argument, base name of traced variable

Argument: idx Standard trace argument, index of traced variable, if an array item

Argument: op Standard trace argument, operation invoking the trace.

TrackVariable (o oldValue)

Configure procedure. Used to track changes to the value of -variable. Removes the traces set upon the old associated variable, then links in the new variable and its contents.

Argument: o The name of the changed option.

Argument: oldValue The value of the option before the change.

updateDisplay ()

Dummy method, must be overridden by derived classes. This one will only throw an error.

watchManager ()

Special constructor. Schedules the execution of the real initialization to happen after the standard initialization and the creation of all component widgets of the derived class.

~watchManager ()

Special destructor. Removes the association between the widget and the variable specified in '-variable', if the latter is not empty. This is accomplished through the deletion of the variable trace set earlier by this widget.

Membervariables

value: The value managed by instances of this class and all its derived classes.

Generated by AutoDoc 2.4 at 09/14/2000, invoked by Andreas Kupries

InitializeManager ()
Special method, is called after the completion of the construction of widget and its components. Initializes the value of the widget according to the contents of the associated variable, if defined.

TrackVarContents (var idx op)
Internal trace callback to monitor the value of the variable associated to the widget.
Argument: var	Standard trace argument, base name of traced variable
Argument: idx	Standard trace argument, index of traced variable, if an array item
Argument: op	Standard trace argument, operation invoking the trace.

TrackVariable (o oldValue)
Configure procedure. Used to track changes to the value of -variable. Removes the traces set upon the old associated variable, then links in the new variable and its contents.
Argument: o	The name of the changed option.
Argument: oldValue	The value of the option before the change.

updateDisplay ()
Dummy method, must be overridden by derived classes. This one will only throw an error.

watchManager ()
Special constructor. Schedules the execution of the real initialization to happen after the standard initialization and the creation of all component widgets of the derived class.

~watchManager ()
Special destructor. Removes the association between the widget and the variable specified in '-variable', if the latter is not empty. This is accomplished through the deletion of the variable trace set earlier by this widget.